Bug 2516875 (CVE-2026-74429)

Summary: CVE-2026-74429 kernel: rxrpc: Fix the reception of a reply packet before data transmission
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's rxrpc component. This vulnerability occurs when the system receives a reply data packet before any request data packets have been sent on a client call. An attacker could potentially exploit this by sending a specially crafted reply packet, leading to a kernel panic or system crash. This could result in a Denial of Service (DoS) for the affected system.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-08-15 06:38:03 UTC 
In the Linux kernel, the following vulnerability has been resolved:

rxrpc: Fix the reception of a reply packet before data transmission

Fix rxrpc_receiving_reply() to handle the reception of an apparent reply
DATA packet before rxrpc has had a chance to send any request DATA packets
on a client call by checking to see if the call has been exposed yet by
sending the first packet.

Without this, rxrpc_rotate_tx_window() might oops.

Also fix rxrpc_rotate_tx_window() to handle the Tx queue being empty by
changing the do...while loop into a while loop, just in case a call is
abnormally terminated by an early reply before the last request packet is
transmitted.
Comment 1 Keith Grant 2026-08-20 22:24:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081514-CVE-2026-74429-fdb4@gregkh/T